Programmed material consolidation methods employing machine vision

ABSTRACT

Programmed material consolidation methods include the use of electronic viewing or machine vision. A feature or location of a support or substrate is recognized or identified and material dispersed relative to the recognized or identified feature or location. The material may be selectively dispensed and at least partially consolidated either actively or passively. By use of the machine vision system, the precise location on a substrate or support element may be determined and communicated to the dispense element of programmed material consolidation system such that a flowable material may be deposited and consolidated at a desired location to form a structural feature.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of application Ser. No. 10/867,258,filed Jun. 14, 2004, pending. The disclosure of the previouslyreferenced U.S. patent application referenced is hereby incorporated byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to systems and methods ofthree-dimensional (3-D) printing. More specifically, the presentinvention relates to systems and methods of 3-D printing for fabricatingfeatures on semiconductor devices and related components.

2. Background of Related Art

Over the past few years three-dimensional (3-D) printing has evolvedinto a relatively promising process for building parts. For example, 3-Dprinting has been used for the production of prototype parts and toolingdirectly from a computer-aided design (CAD) model.

3-D printing of solid structures utilizes a computer, typically undercontrol of computer-aided design (CAD) software, to generate a 3-Dmathematical model of an object to be fabricated. The computermathematically separates, or “slices,” the model into a large number ofrelatively thin, parallel, usually vertically superimposed layers. Eachlayer has defined boundaries and other features that correspond to asubstantially planar section of the model and, thus, of the actualobject to be fabricated. A complete assembly or stack of all of thelayers defines the entire model. A model which has been manipulated inthis manner is typically stored and, thus, embodied as a CAD computerfile. The model is then employed to fabricate an actual, physical objectby building the object, layer by superimposed layer.

One particularly effective 3-D printing system, commercially availablefrom Objet Geometries Ltd. of Rehovot, Israel, is the Eden 330®. Inoperation, the Eden 330® deposits a layer of photopolymer material viainkjet type of printer heads onto a support. For example, layers as thinas 16 μm at a 600×300 dpi (dot per inch) resolution may be deposited ina selected location using the printer heads currently available. Aftereach deposition of the layer of photopolymer, an ultraviolet (UV) lightis used to cure and harden each layer. The process is repeated byselectively depositing additional photopolymer to form an additionallayer, followed by subsequent curing until the complete 3-D CAD model isformed. Other 3-D printing systems and methods are described in detailin U.S. Pat. Nos. 6,658,314; 6,644,763; 6,569,373; and 6,259,962assigned to Objet Geometries Ltd., the disclosure of each of whichpatents is hereby incorporated herein in its entirety by this reference.

Conventionally, 3-D printing systems, such as the aforementioned Objetsystems, have been used to fabricate freestanding structures. Suchstructures have been formed directly on a platen or other support systemof the 3-D printing system. Complicated geometries having overhangs andundercuts may be formed by employing a support material, which thestructure is formed on, followed by removing the support material bydissolving the support material in water. As the freestanding structuresare fabricated directly on the support system and have no physicalrelationship to other structures at the time they are formed, there istypically no need to precisely and accurately position features of thefabricated structure. Accordingly, conventional 3-D printing systemslack image sensors for ensuring that structures are fabricated atspecific, desired locations. However, precise and accurate positioningof features of structures fabricated using a 3-D printing system wouldbe particularly important if the structures were to be 3-D printed, onor immediately adjacent to, another object, such as a semiconductordevice, an assembly including a semiconductor device and othercomponents, or an assembly incorporating one or more semiconductordevices carried, for example, on a carrier substrate such as a printedcircuit board.

Stereolithography has been used in the past to form a variety offeatures on semiconductor assemblies, such as underfill andencapsulation structures. The stereolithography techniques employedtypically involve immersing the semiconductor assembly to apredetermined depth in a liquid photopolymerizable resin and selectivelycuring portions of the liquid resin by rastering with a laser beam toform the desired structures. Examples of stereolithography systemssuitable for forming a variety of features on a semiconductor assemblyare disclosed in U.S. Pat. No. 6,537,482 to Farnworth and U.S. patentapplication Ser. No. 10/705,727 to Farnworth, both of which are assignedto the assignee of the present application. The disclosure of each ofthe foregoing documents is hereby incorporated herein in its entirety bythis reference.

While the above-referenced Farnworth patent and patent applicationdisclose forming a variety of different structures on a semiconductorassembly, the disclosed immersion-type stereolithography processesrequire the use of an excess amount of expensive photopolymer material.This is because only a portion of the liquid photopolymerizable resin iscured to form a structural element while the remaining liquid resin mustbe drained and cleaned from the semiconductor assembly. Furthermore, theprocessing time using immersion-type stereolithography systems issignificantly slower than the processing time for a 3-D printing system,such as the aforementioned Objet systems.

Accordingly, there is a need for 3-D printing systems which areconfigured to form structures on substrates, such as semiconductorsubstrates and semiconductor device components, and which includesystems for accurately positioning the fabricated structures duringformation thereof.

SUMMARY OF THE INVENTION

The present invention, in a number of embodiments, includes programmablematerial consolidation systems for precisely fabricating 3-D structureson a substrate. In addition, the present invention includes methods thatemploy the systems of the present invention and the resulting structuresformed by such methods.

One aspect of the present invention encompasses programmable materialconsolidation systems for fabricating objects. The systems include atleast one dispense element that operates under the control of at leastone controller, a dispense element positioner for effecting movement ofthe dispense element, and a machine vision system. The dispense elementmay be configured for selectively depositing a variety of differenttypes of flowable materials for forming the objects on or over asubstrate. The at least one controller may “read” data from a CAD filecontaining the geometric configuration of the object to be formed andcontrol the operation of the dispense element. A consolidator, undercontrol of the at least one controller, may be employed for at leastpartially consolidating the deposited flowable material.

The machine vision system of the present invention enables the precisedeposition of flowable material in a desired location on or over thesubstrate. The machine vision system includes an optical detectionelement, such as a camera, as well as a controller or processingelement, such as a computer processor or a collection of computerprocessors, associated with the optical detection element. The opticaldetection element may be positioned in a fixed location relative to thesubstrate, mounted on the dispense element, enabling movement thereofover a substantial portion of the substrate, or moveable independentlyof the dispense element over a substantial portion of the substrate. Theoptical detection element of the machine vision system is useful foridentifying the locations of recognizable features, including, withoutlimitation, features on a substrate and features, such as fiducial marksor other objects at a fabrication site, and features that have beenformed on or over the substrate or at the fabrication site.

Another aspect of the present invention encompasses a semiconductorpackage for packaging an array of optically interactive semiconductordevices. An array of optically interactive semiconductor devices on asemiconductor substrate may be surrounded by a support structure formedfrom a consolidated material such as, for example, a cured photopolymermaterial. The support structure may support at least one lens forfocusing light onto the array of optically interactive semiconductordevices and an infrared (IR) filter for filtering IR wavelength lightincident on the array. Methods are also disclosed employing programmablematerial consolidation systems of the present invention to form thesupport structures from consolidatable materials.

Another aspect of the present invention encompasses a method of formingreadily removable mask elements on a substrate employing theprogrammable material consolidation system of the present invention andthe resulting mask element structures. A substrate is provided uponwhich mask elements will be formed. A flowable consolidatablesacrificial material, such as a water soluble photopolymer, may bedispensed from at least one dispense element of the system in apredetermined location on the substrate. The flowable consolidatablesacrificial material is at least partially consolidated to form at leastone mask element. A flowable consolidatable material, such as a liquidphotopolymerizable resin, may be applied to the substrate including themask element followed by at least partially consolidating the flowableconsolidatable material to form a structure that substantially surroundsthe at least one mask element along its periphery with the mask elementexposed therethrough. The at least one mask element may then be removedby exposing the at least one mask element to a solvent to selectivelydissolve the mask element without substantially removing thesubsequently formed structure. For example, by removing the maskelements, apertures may be formed in a dielectric layer providing accessto redistribution lines of a semiconductor device.

These features, advantages, and alternative aspects of the presentinvention will be apparent to those skilled in the art from aconsideration of the following detailed description taken in combinationwith the accompanying drawings. In the detailed description whichfollows, like features and elements in the several embodiments areidentified in the drawings with the same or similar reference numeralsfor the convenience of the reader.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, which illustrate what is currently considered to be thebest mode for carrying out the invention:

FIG. 1 is a block diagram of an exemplary programmable materialconsolidation system of the present invention.

FIG. 2A is a schematic of an exemplary machine vision system utilized inconjunction with the programmable material consolidation system of FIG.1.

FIG. 2B is a schematic of another exemplary machine vision system havinga scan element to position a camera over selected portions of asubstrate.

FIG. 2C is a schematic diagram of yet another exemplary machine visionsystem that includes a camera secured to the inside of the housing ofthe programmable material consolidation system of FIG. 1.

FIG. 3A is a sectional view of a support structure for supporting aninfrared (IR) filter and a plurality of lenses of an opticallyinteractive semiconductor device.

FIG. 3B is a perspective view of the support structure shown in FIG. 4A.

FIGS. 4A-4C illustrate a method of forming a mask element and asubsequent structure using the programmable material consolidationsystem of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a block diagram of an exemplary programmable materialconsolidation system 10 for 3-D printing objects that employs a machinevision system 20 enabling the accurate deposition of flowable material28 for forming a variety of different structures. One suitableprogrammable material consolidation system 10 is the commerciallyavailable Eden 330® manufactured by Objet Geometries Ltd. of Rehovot,Israel, that is modified to include a machine vision system 20 inaccordance with the present invention. Suitable programmable materialconsolidation systems and processes designed by Objet Geometries Ltd.are described in the aforementioned U.S. Pat. Nos. 6,658,314; 6,644,763;6,569,373; and 6,259,962. Of course, teachings of the present inventionare also applicable to other kinds of deposition type programmablematerial consolidation systems such as those commercially available fromOptomec Design Company of Albuquerque, N. Mex. and described in U.S.Pat. Nos. 6,251,488; 6,268,584; 6,391,251; and 6,656,409, the disclosureof each of which patents is hereby incorporated herein in its entiretyby this reference.

Referring to FIG. 1, programmable material consolidation system 10includes a CAD system 12 that includes a CAD computer file stored inmemory (e.g., random-access memory (RAM)). The CAD computer file,typically in .stl file format or other suitable file format, containsthe geometric configuration of the structure to be formed. The CADsystem 12, which may be a desktop computer, is operably coupled to aprocess controller 14. The process controller 14 may be associated withthe CAD system 12 or may be an additional computer or a computerprocessor, which may be programmed to effect a single function or anumber of different functions. Each process controller 14 may beassociated with a single programmable material consolidation system 10or a plurality of systems to coordinate the operation of such systemsrelative to each other. The process controller 14 is operably coupled toa dispense element 16, a dispense element positioner 22, a consolidator18, and a machine vision system 20.

With continued reference to FIG. 1, the dispense element 16 may includea plurality of nozzles 26 configured to selectively deposit flowablematerial 28 in a precise, predetermined amount. For example, currentObjet nozzle technology enables forming layers as thin as 16 μm at600×300 dpi as deposited on a substrate 30. As used herein, the term“dispense element” includes any structure configured to dispensematerial in a directed manner. The material dispenser 24 dispenses theflowable material 28 to the dispense element 16. The material dispenser24 is a receptacle or similar apparatus for holding and enclosing theflowable material 28 from being prematurely consolidated or otherwisereceiving contaminants. The material dispenser 24 may be containedwithin the dispense element 16 or may be located outside the dispenseelement 16 and configured to communicate the flowable material 28 to thedispense element 16. The programmable material consolidation system 10of the present invention may employ a plurality of material dispensers24, wherein each respective material dispenser 24 contains a differentflowable material 28. The nozzles 26 may be configured and tuned todeposit various types of flowable materials 28. The dispense element 16may also be configured so that individual nozzles of the plurality ofnozzles 26 may deposit different types of flowable materials 28 uponreceiving instructions from the process controller 14.

Suitable flowable materials 28 for use with the aforementioned Objetsystems include photopolymers, such as DI 7090 Clear Coat manufacturedby Marabuwerke Gmbh & Co. of Tamm, Germany. Additional suitable flowablematerials include ACCURA® SI 40 HC AND ACCURA® SI 40 ND materialsavailable from 3D Systems, Inc., of Valencia, Calif. Other suitabletypes of flowable material 28 include particulate filled photopolymershaving a plurality of discrete particles formed from elemental metals,alloys, ceramics, or mixtures thereof. Thus, various photopolymers maybe employed for the flowable material 28 having tailorable physical andmechanical properties. Preferably, the photopolymers are ultraviolet(UV) or infrared (IR) curable materials. Other suitable flowablematerials 28 may include powdered metals, ceramics, and mixturesthereof. As used herein, the term “flowable material” means a materialsuitable for dispensing or projecting in a stream or otherunconsolidated mass. One example of a flowable material is a fluid inthe form of a gas, a liquid, or viscous liquid which may optionallycontain a plurality of particles dispersed therethrough. Another exampleof a flowable material is a plurality of particles that are finelydivided, such as a powdered material, so as to be able to flow as astream or other unconsolidated mass of material at least until theparticles are substantially consolidated. The consolidator 18, which maybe an IR or UV light source, may be used to fully cure or at leastpartially cure, to at least a semisolid state, the deposited flowablematerial 28. The consolidator 18 may also be a radiation source, such asa laser, suitable for consolidating powdered materials dispensed fromdispense element 16 (e.g., powdered metals/alloys, ceramics, or mixturesthereof).

The dispense element 16 may be operably coupled to a dispense elementpositioner 22 that may include a stepper motor or a driver for theaccurate positioning of the dispense element 16 and associated nozzles26 over a desired location on a substrate 30 supported by a support 32.The dispense element positioner 22 may effect movement of the dispenseelement 16 in an X and Y direction in the plane of the support 32 and aZ direction substantially perpendicular to the plane of support 32. Thetypes of substrates 30 that support 32 may be configured to carry mayinclude, without limitation, a bulk semiconductor substrate (e.g., afull or partial wafer of semiconductor material, such as silicon,gallium arsenide, indium phosphide, a silicon-on-insulator (SOI) typesubstrate, such as silicon-on-ceramic (SOC), silicon-on-glass (SOG), orsilicon-on-sapphire (SOS), etc.) that includes a plurality ofsemiconductor devices thereon, printed circuit boards (PCBs), singulatedsemiconductor dice, singulated semiconductor dice in process assembledwith one or more additional components, chip scale and largersemiconductor device assemblies, and associated electronic components.

The programmable material consolidation system 10 of the presentinvention includes a machine vision system 20. Referring to FIG. 2A, themachine vision system 20 includes a camera 34 and a computer 36 having amotherboard 38, a processor 40 and associated memory 42. In FIG. 2A, anexemplary embodiment of machine vision system 20 is depicted, whereinthe camera 34 moves with the dispense element 16 such that the camera 34may be controllably moved over the entire surface 46 of the substrate30. For example, the camera 34 may be fixed or mounted to the dispenseelement 16. Dispense element 16, under control of the computer 36,positions camera 34 in close proximity to (e.g., inches from) surface 46of the substrate 30 and to volume 50 of uncured flowable material 28 soas to enable camera 34 to view minute features on the substrate 30(e.g., bond pads, conductive traces, fuses, or other circuit elements ofa semiconductor device) that are located at or near surface 46. Uponviewing substrate 30, camera 34 communicates information about theprecise locations of such features (e.g., with an accuracy of up toabout ±0.1 mil (i.e., 0.0001 inch)) to computer 36 of machine visionsystem 20.

A response by computer 36 may be in the form of instructions regardingthe operation of the programmable material consolidation system 10.These instructions may be embodied as signals, or carrier waves. By wayof example only, such responsive instructions may be communicated to theprocess controller 14 of programmable material consolidation system 10.Process controller 14 may, in turn, cause the programmable materialconsolidation system 10 to operate in such a way as to effect thefabrication of one or more objects on substrate 30 precisely at theintended locations thereof.

Camera 34 may comprise any one of a number of commercially availablecameras, such as charge-coupled device (CCD) cameras or complementarymetal-oxide-semiconductor (CMOS) cameras available from a number ofvendors. Of course, the image resolution of camera 34 should besufficiently high as to enable camera 34 to view the desired features ofsubstrate 30 and, thus, to enable computer 34 to precisely determine thepositions of such features. In order to provide one or more referencepoints for the features that are viewed by camera 34, camera 34 may also“view” one or more fiducial marks 44 on the support 32.

Suitable electronic componentry, as required for adapting or convertingthe signals, or carrier waves, that are output by camera 34, may beincorporated on motherboard 38 installed in a computer 36. Suchelectronic componentry may include one or more processors 40, othergroups of logic circuits, or other processing or control elements thathave been dedicated for use in conjunction with camera 34. At least oneprocessing element, which may include a processor 40, another, smallergroup of logic circuits, or other control element that has beendedicated for use in conjunction with camera 34, is programmed, as knownin the art, to process signals that represent images that have been“viewed” by camera 34 and respond to such signals.

A self-contained machine vision system available from a commercialvendor of such equipment may be employed as machine vision system 20.Examples of such machine vision systems and their various features aredescribed, without limitation, in U.S. Pat. Nos. 4,526,646; 4,543,659;4,736,437; 4,899,921; 5,059,559; 5,113,565; 5,145,099; 5,238,174;5,463,227; 5,288,698; 5,471,310; 5,506,684; 5,516,023; 5,516,026; and5,644,245. The disclosure of each of the immediately foregoing patentsis hereby incorporated herein in its entirety by this reference. Suchsystems are available, for example, from Cognex Corporation of Natick,Mass. As an example, and not to limit the scope of the presentinvention, the apparatus of the Cognex BGA Inspection Package™ or theSMD Placement Guidance Package™ may be adapted for use in a programmablematerial consolidation system 10 that incorporates teachings of thepresent invention, although it is currently believed that the MVS-8000™product family and the Checkpoint® product line, the latter employed incombination with Cognex PatNax™ software, may be especially suitable foruse in the present invention.

Referring to FIG. 2B, in another exemplary embodiment, a camera 34′ maybe mounted on a scan element 90 operably coupled to and controlled bycomputer 36. The scan element 90 enables movement of the camera 34′ overa substantial portion of the surface 46 of the substrate 30. Thus, thecamera 34′ may be moved independent of the dispense element 16 so thatit does not interfere with the dispense element 16 during operationthereof.

Due to the close proximity of camera 34′ to surface 46, the field ofvision of camera 34′ is relatively small. In order to enable camera 34′to view a larger area of surface 46 than that which is “covered” by, orlocated within, the field of vision of camera 34′, a scan element 90 ofa known type is configured to traverse camera 34′ over at least part ofthe area of surface 46. Scan element 90 is also useful for moving camera34′ out of the path of any selectively consolidating energy beingdirected toward surface 46 from the consolidator 18 or any flowablematerial 28 being dispensed by the dispense element 16 on or over thesurface 46. By way of example only, scan element 90 may comprise an X-Yplotter or scanner of a known type. Generally, an X-Y plotter or scannerincludes an x-axis element 91 and a y-axis element 92 that intersect oneanother. As depicted, camera 34′ is carried by both x-axis element 91and y-axis element 92 and, thus, is positioned at or near the locationwhere x-axis element 91 and y-axis element 92 intersect one another.

X-axis element 91 and y-axis element 92 are both configured to moverelative to and, thus, to position camera 34 at a plurality of locationsover the substrate 30. Movement of x-axis element 91 is effected by anactuator 96 (e.g., a stepper motor and actuation system, such as a gearor wheel that moves x-axis element 91 along a track) that has beenoperably coupled thereto, with actuator 96 being configured to causex-axis element 91 to move laterally (i.e., perpendicular to the lengththereof) along a y-axis. Y-axis element 92 is operatively coupled to anactuator 94, which is configured to cause y-axis element 92 to movelaterally along an x-axis. Actuators 94 and 96 may be configured to movetheir respective x-axis element 91 and y-axis element 92 in asubstantially continuous fashion or in an incremental fashion. Movementof actuators 94 and 96 may be controlled by computer 36.

FIG. 2C shows another exemplary embodiment of machine vision system 20that includes a locationally stationary camera 34″. The camera 34″ maybe mounted or otherwise secured in a fixed position relative to surface46 and may be maintained in a fixed position relative to the housing 48.In FIG. 2C, the camera 34″ is shown fixed to the inside wall 47 of thehousing 48 that encloses at least the dispense element 16 and associatednozzles 26. The camera 34″ is mounted in a position so that it does notinterfere with the operation and movement of the dispense element 16. Aswith the camera 34 and 34′, the camera 34″ is operably coupled tocomputer 36 having board 38 and at least one processor 40.

Like camera 34 and 34′, which are described with reference to FIGS. 2Aand 2B, camera 34″ may comprise a CCD camera, a CMOS camera, or anyother suitable type of camera. As camera 34″ is positioned farther awayfrom a substrate 30 to be viewed, the camera 34″ may have an effectivelylarger field of vision than camera 34. Of course, suitable opticaland/or digital magnification technology may be associated with camera34″ to provide the desired level of resolution. Further, although camera34″ may be locationally stationary, a suitable gimbals structure withrotational actuators may be employed to point camera 34″ at a specificlocation in the field of exposure with little actual rotationalmovement. Thus, camera 34″ may be used for both broad, or “macro,”vision and viewing and inspection of miniature features.

The operation of the programmable material consolidation system 10 willbe better understood by reference to the specific examples illustratedin FIGS. 3A and 3B and FIGS. 4A-4C. The programmable materialconsolidation system 10 of the present invention may be employed tofabricate a variety of structures on semiconductor substrates. Forexample, the programmable material consolidation system 10 may be usedto fabricate support structures or mask elements in selected positionson a semiconductor substrate, wherein the selected positions areaccurately located by the machine vision system 20 of the presentinvention.

With reference to FIGS. 3A and 3B, in order to 3-D print supportstructure 62 on semiconductor substrate 52, corresponding data from the.stl files, which comprise a 3-D CAD model, stored in memory associatedwith process controller 14 are processed by the process controller 14.The data, which mathematically represents the support structure 62 to befabricated, may be divided into subsets, each subset representing alayer 68, or “slice,” of the object. The division of data may beeffected by mathematically sectioning the 3-D CAD model into at leastone layer 68, a single layer or a “stack” of such layers 68 representingthe support structure 62. Each slice may be, for example, about 16 μmthick or any other desirable thickness. As used herein, the term “layer”or “slice” is not limiting as to any specific x- and y-plane dimensionor z-plane thickness, and layers or slices may be extremely minute andnot necessarily fully mutually superimposed, as it is contemplated thatflowable materials 28 may be applied in extremely small quantities andsubstantially instantaneously cured to at least a semisolid state sothat, at least for small distances, structures may be cantilevered.

Again referring to FIG. 3A, a sectional view of an optically interactivesemiconductor device 66 is shown. A support structure 62 is depictedthat supports a plurality of lenses 60 a-60 c and an infrared (IR)filter 58. Semiconductor substrate 52 includes at least one array 56 ofoptically interactive semiconductor devices such as, for example, CCDimage sensors or CMOS image sensors on its active surface 53. Thesemiconductor substrate 52 may also be a bulk substrate comprised of aplurality of semiconductor dice locations, each containing an array 56of optically interactive semiconductor devices. Each array 56 ofoptically interactive semiconductor devices may be substantiallysurrounded along its periphery by the support structure 62 includingledges 64A-64G that support a plurality of lenses 60 a-60 c for focusinglight onto the array 56 and an IR filter 58. As known in the art, the IRfilter 58 and the plurality of lenses 60 a-60 c may be fixed to thesupport structure 62 using an adhesive. Support structure 62 may beformed from any of the aforementioned flowable materials 28. The array56 of optically interactive semiconductor devices may also be coveredwith a protective layer 57 formed from an optically clear flowablematerial 28. One suitable optically clear flowable material 28 is theObjet FullCure S-705 photopolymer support material commerciallyavailable from Objet Geometries Ltd. of Rehovot, Israel. Although notshown in FIG. 3A, it should be understood that the semiconductorsubstrate 52 may include external conductive elements for electricallyconnecting semiconductor substrate 52 to other semiconductor devices orhigher level packaging, such as a printed circuit board. FIG. 3Billustrates a perspective view of the optically interactivesemiconductor device 66 having the support structure 62 disposed onsemiconductor substrate 52.

The package for the optically interactive semiconductor device 66 may befabricated using the programmable material consolidation system 10 ofthe present invention. The semiconductor substrate 52 is provided on thesupport 32. The camera 34 of the machine vision system 20 locates thedesired location adjacent the periphery of the array 56 that flowablematerial 28 is to be deposited on the semiconductor substrate 52. Thedispense element 16 selectively deposits a layer 68 of flowable material28 at the desired location by movement of the dispense element 16 undercontrol of the process controller 14 to partially form support structureelement 62A followed by the consolidator 18 at least partiallyconsolidating the layer 68 of flowable material 28. The supportstructure elements 62A-62H are formed by selectively depositing theflowable material 28 in desired locations layer 68 by layer 68 (shown bythe dashed lines in FIG. 3A) followed by at least partiallyconsolidating each layer 68 with the consolidator 18 before thedeposition of another layer, until the complete support structure 62 isso formed. The protective layer 57 is formed in the same manner bybuilding up the protective layer 57 using one or more superimposedlayers. Prior to the deposition of each layer 68, the camera 34 of themachine vision system 20 may be used to verify that the depositedflowable material 28 was deposited in the desired location onsemiconductor substrate 52 or a prior layer 68, or the camera 34 may beused to identify and precisely locate another position for the selectivedeposition of the flowable material 28. The camera 34 may also be usedto perform the verification just after the deposition of the flowablematerial 28 is initiated. Also, it should be understood that the numberof layers that are required to form support structure elements 62A-62Hand the protective layer 57 depends upon the desired height of thesupport structure elements 62A-62H that comprise the support structure62.

In another exemplary embodiment illustrated in FIGS. 4A-4C, the 3-Dprinting system of the present invention may also be used to form aplurality of removable/sacrificial mask elements. A simplified sectionaldrawing of a portion of a semiconductor substrate 70 having an activesurface 74 and a back surface 72 is shown in FIG. 4A. An electricalcontact 76 in the form of a bond pad is shown, which is in electricalcommunication with an integrated circuit formed within the semiconductorsubstrate 70 on active surface 74. A redistribution line 82 in the formof a conductive trace is depicted being in electrical communication withthe electrical contact 76 and extending over dielectric layer 78therefrom. Of course, in practice, semiconductor substrate 70 would beara large plurality of electrical contacts 76, each of which having anassociated redistribution line extending to another location over theactive surface 74 for redistributing the I/O pattern of the integratedcircuit for connection to external circuitry.

Again referring to FIG. 4A, a layer of flowable material 28 that is asacrificial/removable consolidatable material, such as a water solublephotopolymer, may be selectively deposited from dispense element 16 on aportion of the redistribution line 82 to form mask element 80 using theprogrammable material consolidation system 10 of the present invention.Suitable water soluble photopolymers for forming the mask element 80 aredisclosed in United States Patent Application Publication 2003/0207959assigned to Objet Geometries Ltd., the disclosure of which is herebyincorporated herein in its entirety by this reference. As previouslydiscussed, mask element 80 may be formed by the deposition of successivelayers 88, with each layer 88 at least partially consolidated byconsolidator 18 before the next layer 88 is deposited. Of course, theprecise number of layers 88 used to form the mask element 80 dependsupon the desired thickness of mask element 80. Furthermore, the machinevision system 20 may be used to locate the portion of the redistributionline 82 on which the mask element 80 is to be formed and to verify afterforming layers of the mask element 80 that they have been formed in thedesired location.

Referring to FIG. 4B, another, more permanent, consolidatable materialmay be selectively applied to the semiconductor substrate 70 having themask element 80 thereon. The application of another consolidatablematerial may be effected employing the programmable materialconsolidation system 10 of the present invention to form a peripheralwall structure 84 from a consolidatable material. Following fabricationof peripheral wall structure 84, which may comprise a plurality ofsequentially applied layers 100, semiconductor substrate 70 includingthe mask element 80 may be immersed in a bath of liquidphotopolymerizable resin 102 such as is used in a stereolithographyapparatus, for example, of the type disclosed in the aforementioned U.S.Pat. No. 6,537,482 to Farnworth, and then raised from the bath. Theresin 102 is thus trapped within wall structure 84 to a level determinedby the height of the wall structure 84. The liquid photopolymerizableresin 102 may then be floodlight-exposed to UV light or subjected toheat to effect a cure thereof. The dielectric layer 104 so formedsurrounds the mask element 80 about its periphery with the mask element80 exposed therethrough. If a liquid photopolymerizable resin isemployed as the consolidatable material to form peripheral wallstructure 84, it may be at least partially consolidated by exposure to asuitable UV point source, such as a laser beam, that irradiates light inthe UV wavelength. Suitable liquid photopolymerizable resins for use inpracticing the present invention include, without limitation, ACCURA® SI40 HC and AR materials and CIBATOOL SL 5170 and SL 5210 resins for theSLA® 250/50HR and SLA® 500 systems, ACCURA® SI 40 ND material andCIBATOOL SL 5530 resin for the SLA® 5000 and 7000 systems, and CIBATOOLSL 7510 resin for the SLA® 7000 system. The ACCURA® materials areavailable from 3D Systems, Inc., of Valencia, Calif., while the CIBATOOLresins are available from Ciba Specialty Chemicals Company of Basel,Switzerland.

Referring to FIG. 4C, the mask element 80 may be removed by subjectingit to a solvent, such as by immersing the semiconductor substrate 70including the mask element 80 in water or another solvent suitable fordissolution of mask element 80 to selectively dissolve the mask element80 into solution and remove the mask element 80. Thus, a plurality ofapertures 86 may be formed in dielectric layer 104 at desired locationsover respective redistribution lines 82 by removing the mask elements80. As known in the art, solder may be deposited within the apertures 86by stenciling or screening and then formed into conducted bumps byheat-induced reflow to provide discrete external electrical contacts forinterconnecting with another semiconductor die or a higher level device.Thus, by employing the removable mask element 80 in combination withperipheral wall structure 84, apertures 86 may be formed without havingto use expensive and time consuming photolithography or electron beamlithography systems. The exemplary embodiment disclosed in FIGS. 4A-4Cis only one example of a type of structure that may be fabricated andwith which the removable material may be used.

Although the foregoing description contains many specifics, these arenot to be construed as limiting the scope of the present invention, butmerely as providing certain exemplary embodiments. Similarly, otherembodiments of the invention may be devised which do not depart from thespirit or scope of the present invention. The scope of the invention is,therefore, indicated and limited only by the appended claims and theirlegal equivalents, rather than by the foregoing description. Alladditions, deletions, and modifications to the invention, as disclosedherein, which fall within the meaning and scope of the claims areencompassed by the present invention.

1. A method for forming three-dimensional structures comprising:providing a support element; electronically viewing at least a portionof the support element to locate an identified area on or over thesupport element; and selectively dispensing unconsolidated materialtoward the identified area.
 2. The method of claim 1, whereinelectronically viewing comprises use of a machine vision system.
 3. Themethod of claim 1, wherein electronically viewing comprises locating afeature support element or a substrate thereon.
 4. The method of claim1, further comprising: at least partially consolidating theunconsolidated material to form at least a portion of a structuralfeature.
 5. The method of claim 4, wherein at least partiallyconsolidating comprises exposing the unconsolidated material toconsolidating energy.
 6. The method of claim 5, wherein exposingcomprises exposing the unconsolidated material to consolidatingradiation.
 7. The method of claim 5, wherein exposing comprises exposingthe unconsolidated material to focused consolidating energy.
 8. Themethod of claim 4, further comprising: electronically viewing thestructural feature.
 9. The method of claim 4, further comprising:locating another identified position on or over the support element. 10.The method of claim 9, further comprising: selectively dispensingunconsolidated material toward the another identified area.
 11. Themethod of claim 10, further comprising: at least partially consolidatingthe unconsolidated material at the another identified area to form atleast a portion of another structural feature.
 12. The method of claim1, wherein selectively dispensing comprises selectively dispensing aphotopolymer.
 13. The method of claim 1, wherein selectively dispensingcomprises selectively dispensing unconsolidated material comprising atleast one of a metal, an alloy, and a ceramic.
 14. The method of claim1, further comprising: positioning a substrate on the support element.15. The method of claim 14, wherein positioning comprises positioning asemiconductor substrate on the support element.
 16. The method of claim15, wherein positioning comprises positioning at least one semiconductordie on the support element.
 17. A method for forming a mask elementcomprising: providing a substrate; selectively dispensing unconsolidatedsacrificial material onto at least one predetermined location of thesubstrate; at least partially consolidating the unconsolidatedsacrificial material; applying unconsolidated material to the substrateand the at least one mask element; at least partially consolidating theunconsolidated material; and removing the sacrificial material.
 18. Themethod of claim 17, wherein at least one of selectively dispensing andapplying is effected in conjunction with a machine vision system. 19.The method of claim 17, wherein removing the sacrificial materialcomprises dissolving the sacrificial material.
 20. The method of claim17, wherein providing the substrate comprises providing at least onesemiconductor die.
 21. The method of claim 20, wherein selectivelydispensing comprises selectively dispensing unconsolidated sacrificialmaterial to at least one predetermined location comprising a contact padand a location for a redistribution line.
 22. The method of claim 17,wherein applying comprises applying a photopolymer.
 23. The method ofclaim 17, wherein selectively dispensing comprises selectivelydispensing a water soluble material.
 24. The method of claim 23, whereinselectively dispensing comprises selectively dispensing a photopolymer.25. A method of packaging a semiconductor device, comprising: providingat least one semiconductor die having a back surface and an activesurface including at least one array of optically interactive elementsthereon; locating a peripheral region of the at least one array ofoptically interactive elements; and selectively dispensing two or moreadjacent, mutually adhered regions of consolidatable material to form asupport structure that substantially surrounds the at least one array.26. The method of claim 25, wherein each region of adjacentconsolidatable material is at least partially consolidated beforedepositing another region thereto.
 27. The method of claim 25, whereinlocating the peripheral region comprises viewing the at least onesemiconductor die using a machine vision system.
 28. The method of claim26, further comprising: viewing each region after dispensing the same.29. The method of claim 25, further comprising: securing an infraredfilter over the at least one array.
 30. The method of claim 25, furthercomprising: securing at least one lens over the at least one array. 31.The method of claim 25, wherein selectively dispensing comprisesselectively dispensing photopolymer.